Pro-evolutionists: Can you claim properly to understand Darwinian natural selection?

Question

A question was just posted asking if evolutionists believed humans are still evolving:

http://tinyurl.com/yepazk

Assuming that someone who DIDN'T believe evolution ever happened would say that we WERE still evolving, the answerers were presumably all persauded that evolution is a well-supported theory and that it resulted in the evolution of modern humans.

It struck me as strange, therefore, that many seemed to think that it is necessary for us STILL to be evolving or the theory is undermined. Evolution may always be happening, but an individual species is not always evolving. An evolutionary biologist would point out that getting healthier or developing better technology is NOT the same as biological evolution.

So much as I dislike challenging those who share my view of evolution -- have you actually read and understood Darwin?

I gave my reasons for saying no at the link above. If you don't agree (fine), I'd like your interpretation of natural selection.

Mirage, in the first place you would be describing sexual selection, not natural selection; and compared to other species there is almost NO competition for mates - nothing to stop the ugliest, weakest or even sickest person finding a mating partner if they want one. Doesn't happen among kangaroos.

Darwin himself, in both the Origin and more particularly the Descent, distinguishes between natural and sexual selection, and rightly: they are responses to entirely different pressures. Sorry, sexual selection is not part of natural selection (the latter is also called, following Herbert Spencer, the "survival of the fittest"). I'll take Darwin over doctionary.com, if that's okay.

No, weak people mating will not result in a gradual dwindling of the gene pool, it will result in the continuation and growth of conditions like colourblindness, diabetes and asthma, and congenital birth defects, which is evident today. Even spectacles lessen the chance of natural selection, removing a threat against survival and imporiving chances of reproduction. Ever wondered if there were any short-sighted hawks?

*****

"Evolution" is not the same as natural selection.
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Answer 1

Evolution is a change in the heritable traits in a population over time. That's it. It is an ongoing process - every time an organism is born or dies the allele frequencies in the population change slightly. Change can be random, genetic drift, or the result of selection. And survival advantages need only be very slight for the trait to increase in frequency in the population.

Natural Selection is the opposite of Artificial Selection - the deliberate selection of breeding stock by humans (Darwin, 1859). And according to the science of today at least, sexual selection IS a part of natural selection (unless you're involved in some sort of eugenics program). It's the theory of evolution by natural selection, not natural selection and sexual selection and kin selection and....

Now, to take your example - our environment has changed such that previously debilitating traits are no longer such a hindrance to many individuals survival. What this demonstrates is that ecological selection is operating to change the frequency of heritable traits in our population. Hence we are evolving with that one simple example.

If you assume that evolution has direction, up-wards progress, then you are making the same basic mistake as many creationists. Besides what is a "weakness" depends only on the environment, eg. type-2 diabetes may have given previous generations protection against famine, and it is an evolutionary asset to have genetic diversity.

Answer 2

Well, I am a biology major, and since we do live in an environment in which there is competition for mates, then certain traits would be favorable, and certain traits would not be favorable. This would suggest that we are still evolving, because as long as there is competition there will be natural selection...

Royal racer: Read the last paragraph...

"natural selection

the process by which forms of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in climate, or competition for food or MATES, will tend to survive and REPRODUCE in greater numbers than others of their kind, thus ensuring the perpetuation of those favorable traits in succeeding generation"

Sexual selection is a part of natural selection, not a different process. And weak people may be reproducing, but they are most likely reproducing with other weak people, resulting in a polarization of our gene pool. Eventually, the weaker ones will dwindle and die out...

- Atmadeepo Bhava -

Answer 3

ok simply?


natural selection promotes stability within a species that is prevents change

that is, natural selection occurs WITHOUT EVOLUTION!

I wonder how many will grasp that????


edit:

I'm not by any means saying that evolution within species does NOT occur

just simply, stating that natural selection also promotes stability within a species

I agree with you bad liberalist, but what's the point in discussing scientific concepts with people with biased interpretations? or worse, no understanding at all?

Answer 4

Darwin never mentioned the word Evolution in his book.

Answer 5

We are still evlving but it takes hundreds of thousands in conditions for a species to thrive in to change, when earth becomes uninhabitable to us our children will detect this in thier dna and genetically alter their children also retard the earth is constently changing so its obvious its always happening, someone as smug as u could have realized that

Answer 6

Yes, I understand evolution.

Answer 7

i gotta be honest, the answers i got for my previous question got me more confused.

every body is saying something different.

you understood my question and your answer made sense to me. because i meant "biological evolution" of the human species.